(optics) defect in an optical system in which light rays from a single point fail to converge in a single focal point1点から発した光線を1つの焦点に集めることのできない、光学システムの欠陥非点収差
(ophthalmology) impaired eyesight resulting usually from irregular conformation of the cornea; common in nearsighted people通常、角膜の不規則な構造から生じる視力障害乱視